Sliding glass doors are widely used in home construction and some commercial installations. In addition, horizontal sliding windows are extensively used in many parts of the United States, particularly in the South and Southwest. Typically, such sliding doors and horizontally sliding windows have a handle on them to facilitate the movement of the door or window. In addition, a separate latching mechanism generally is provided to secure the door or sliding window in the closed position.
Sliding doors which currently are available typically employ one or the other of two different types of latches or locks. One of these locks is a mortise type, which is concealed in the hollow of the stile extrusion, and is connected to the catch by a movable hook. This is a relatively flimsy latching mechanism, because of size constraints which must be employed in the movable hook which is rotated into position by means of a rotating lever mounted on the door. In addition, damage can occur to the catch or opening if the door is forcefully closed when the latching hook is in its "latched" position prior to full closure of the door. This may cause a bending or a breaking of the catch opening and frequently results in failure of the latching mechanism.
Another popular closure latch for use with sliding glass doors is a "clam surface" lock. This lock, again, is operated by a pivoting lever on the door to cause an "L-shaped" latch to pivot toward and away from the door frame. A projection or flange is located on the frame adjacent the location of this pivoting clam lever; so that when the lever is pivoted toward the door to overlie the flange, the door is latched or prevented from being opened. Rotation of the clam latching member outwardly away from the door then clears the flange to permit the door to be opened and closed. Such "clam surface" locks for sliding glass doors generally are preferable to the mortise type discussed above, but still provide a relatively weak latch, because of the restricted area of contact provided by the latching mechanism. In addition, it is necessary to have rotating parts, springs, cams and the like in a multiple part assembly to produce such a pivoting clam surface lock.
For both the mortise type locks and the clam surface locks described above, the locking mechanism is separate from the handle, which is grasped to open and close the door or sliding window. The result is additional cost for the various separate components.
It is desirable to provide an improved latching mechanism for sliding doors and horizontally sliding windows, which is simple and efficient to manufacture and use, and which overcomes the disadvantages of the prior art.